In the semi-automatic control system disclosed in my copending application Ser. No. 871,490 filed Jan. 23, 1978, now U.S. Pat. No. 4,175,688 and entitled Semi-Automatic Stock Feeder the main valve means for controlling the fluid motor means of the pneumatic feeders described therein are adapted to be controlled by a three-way trigger valve unit and a serially coupled cut-off valve unit. These two separate valve units may be advantageously simplified. It has been found that under some operating conditions the proper sequencing of actuation of stock gripping motors and feed slide motors is more difficult to achieve with feeders that have longer feed strokes such as twelve inches or more. Further it is desirable to have some sort of circuit safety means for preventing an inadvertent initiation of a feed-index cycle of movement of the feed slide due to occasional small random pressure leaks that may develop in the elements of the associated control circuit.